"We improved a lot today and we put in a good performance," said Bortolami. "We have some young players and they need experience. It was terrible against Canada, better against Tonga but today was a real improvement."
Fly-half Riccardo Bocchino opened the scoring following a dominant scrum from the Italians in the opposition '22 and Tito Tebaldi converted.
A penalty from Etimoni Paea narrowed the margin after 16 minutes but was quickly followed by three points from the Azzurri after indiscipline at the breakdown from the Tongans.
Bocchino chipped away at the scoreboard with a second successful penalty, while the Tongans continued to make dents with their typically ferocious tackles but failed to make a further impression on the scoreboard before half-time.
A sprightly start to the second half saw Italy advance further with Tebaldi again slotting his third successful penalty to take his side 13-3 ahead.
With momentum on their side, the Italians found an injection of flair when Joshua Furno's dummy pass on the wing set Andrea Pratichetti up for the Italians' second try.
Having struggled to conjure a try during 50 minutes of play, the Tongans showed up in style as Viliami Iongi struck from just inside the 22, weaved through a handful of defenders and scored in the corner. The conversion was missed to leave Tonga 12 points behind.
A period of exchanges between the two sides ended when Etimoni Paea slotted a further three points for the Tongans, narrowing the margin to nine points.
Giovanbattista Venditti scored a try to equal the panash of Iongi's, sprinting the length of the pitch to score his side's third try.
A try in the closing minutes from Mateo Malupo and a conversion from Kurt Morath was but consolation for Tonga.
Tonga: M Malupo; V Helu (K Morath 41), S Hufanga, T Sili (S Fonua, 54), V Iongi; E Paea, S Havea (D Morath 75); O Fainga'anuku (M Latu 44), A Halangahu (Telefoni, 75), K Pulu, J Afu, E Kauhenga, S Timani, P Kaho (P Koloamatangi 53), P Mapakaitolo (T Ula 28).
Scorers: Tries: Iongi, Malupo; Pens: Paea, K Morath; Con: K Morath
Italy A: D Gerber (G Toniolatti, 67), G Venditi, A Pratichetti, M Pratichetti, A Esposito (N Belardo, 65); R Bocchino, T Tebaldi; M Aguero ( De Marchi, 57), T D'Apice (A Manici, 75), F Staibano (D Chistolini, 40), J Furno, M Bortolami (capt, R Trevisan, 75), L Petillo, F Minto (V Bernabo, 65), M Vosawai.
Scorers: Tries: Bocchino, Pratichetti, Venditti; Cons: Tebaldi (3); Pens: Tebaldi (2)
Referee: N Owens (Wales)